Hard to say...the prices are all over the map. If all her accessories are there, and if the machine head is in good condition and the cabinet is good and the irons are good....see what I mean...there are so many variables. You can kind of judge how much it would cost you to replace anything missing or that needs repair. Start with a base of about $100-125 and subtract for missing/damaged items from there. I got a model 15 in a straight leg treadle that is dated 1956 for $75. I'm in CA. I really wouldn't go over $125 unless you really really want it and it's in really really good shape.

It all depends on condition and model. I didn't look this up but Singers are generally a dime a dozen. And as jljack said it depends. I am even harder then her as this is a plain cabinet so would start at around $50 and then deduct from there.

Hm, having acquired multiple treadles and been all over Craigslist for my state and neighboring, I can tell you this fact, prices range from 'come take, to d@#% ridiculous.

A machine's worth is based on how much you want that particular machine. Everything else is second. Because I had an 'eagle eye' and spotted a cabinet buried under magazines and tools, I became the owner of an almost pristine Singer 66, Red Eye. You can view it here - Meet 'Charlee', a 1920 Singer 66-1 (Pic heavy) We paid $40 for her.

If the pin rash and missing decals are of no consequence to you, and the machine is in working order and you want it, go for. Otherwise, hold off. Red Eyes are a dime a dozen.